Brighton bloggers unite into a community more than in many larger cities. Photograph: Peter Dench/Corbis

Blogs are changing. What appeared at first to be a solitary occupation behind closed doors has spawned award ceremonies, social gatherings and networking events - and it's inspired this roundup of the liveliest cities in the UK for blogging.

The criteria will of course be contentious. Even the definition of a city can be less than straightforward. We're running with the EU definition of a city as having 20,000 inhabitants.

How to define a local blog is also tricky. Is it one about a region and so something that could be written anywhere? Or is it a collection of writings by somebody local even if the content isn't particularly specific to an area? We plumped for items written in regions about the same regions wherever possible, although we acknowledge the approach won't be perfect.

Brighton

Brighton's size may dictate that it doesn't have as many blogs happening as London, but the same limitation leads its bloggers to cohere more as a community than in many of the larger cities. There is an aggregator site, brightonbloggers.com, and an award scheme.

Rosie Sherry runs three of her own blogs and is starting another in collaboration with three Brighton-based technology bloggers, to be called projectbrighton.com. She sees blogs as having many strengths. "Blogs are mostly honest and readers get to know the writers, gaining confidence in them," she says. "Also many blogs are very focused and the information is often not found anywhere else." Fellow Brighton blogger Tom Hume (tomhume.org) agrees. "[A blog] avoids editorial bias other than the writer's own. It's easier to appeal to niche communities."

Cardiff

The difficulty in deciding whether or not Cardiff is a heavily blogged city is two-fold: first, as I am unable to speak Welsh my investigations were limited to blogs in English, and second, many of the blogs in the area are tied to things other than the locality. At the risk of sounding anoraky, the typical science fiction fan will be very into new technologies like blogs - and since Cardiff is where they film Doctor Who, whenever there's any sign of a police box the bloggers go crazy.

Maths teacher and former software developer Rhys Jeremiah blogs about other things, mostly career-related, with a view to promoting himself as a potential employee on the Hairy Spider Blog (hairy-spider.com). He also sees blogging as a progression of journalism: "Blogs are generally written by enthusiasts and as such the quality of the information contained in a blog article is generally better than you could expect from a newspaper," he says. "Obviously the other massive advantage that blogs have over print is the speed in which articles can be published, reviewed and commented on."

Edinburgh

Scotland's capital attracts a huge number of bloggers during its annual festival. We classified these as comedy blogs, but there's a lot going on outside of this niche - as you'd expect from a city with such a large student population.

John Jones started The Edinburgh Blog (theedinburghblog.co.uk) because he was frustrated with so much of what was already published about his home town. "Typing a keyword into a search engine doesn't necessarily mean the content returned will be relevant, nor will it be truthful," he says. "I really wanted to put some handwritten, hand-researched content whose aim was to inform my readership about local things to do, where to eat."

A more political tone accompanies all of the posts from edinburghsucks.com, run by a man who calls himself only The Basa, to highlight what he and his friends perceive as inconsistencies in the Scottish parliament's actions. "It seems that election time is when the traffic spikes - we have been mentioned on Radio 4 a couple of times and we had spikes then."

London

Inevitably, the UK's capital has spawned many blogs and blog-listing sites. One of the more leftfield is London Bloggers (londonbloggers.iamcal.com) which categorises them according to whichever tube station is nearest to the writer.

As in Edinburgh, eating and drinking are popular discussion areas. Ben Bush co-writes Food and Drink in London (londonfood.typepad.com/stuff), which started as an extension of discussions he and a friend were having about eating out in the city. He much prefers blogging to the idea of standard restaurant reviewing. "We're not restricted by publishing deadlines, word counts, static imagery, editorial policy ... It's also obviously a far more dynamic environment when it comes to receiving and responding to readers' comments and questions," says Bush.

Possibly because of its sheer size, the blogging community in London seems a lot more disparate than in some of the other places here .

Manchester

Mancunians appear second only to Brightonians in setting up a network of blogs. The Manchizzle (manchizzle.blogspot.com) is a good place to start, run by Kate Feld. "Because I'm one of the main organisers of the city's bloggers, my site has ended up as a kind of hub for online Mancunian writing," she says.

Blogging started early in the city. The Manchester Evening News was quick to descend on proto-blogger Aidan O'Rourke when he started writing an online diary. He sees blogging and newspapers as separate entities, though. "A blog is personal, a newspaper is produced by a team," he says. "In my former site, Eyewitness in Manchester - a kind of forerunner to a blog - I was able to give a personal slant independent of the standard newspaper way of doing things. People appreciated that. The Manchester Evening News site Manchester Online offered me a contract to produce it as a freelance contributor. That was from 1998 to 2005."

Manchester also attracted the BBC's attention, and its blog at bbc.co.uk/blogs/manchester is one of its livelier sites. According to one of its organisers, Robin Hammam, blogging is a lot more than just publishing content online. "It's a way of seeking out and engaging with what bloggers call 'the conversation'," he says. "I think it's essential for anyone working in a creative or knowledge industry to blog, or at least participate in discussions, otherwise they risk falling behind. The point of the BBC Manchester Blog isn't just about our posts - what we're trying to do is quote from and link to some of the best local blog content, which deserves the attention of a wider audience."

It's clear blogging is still very much a medium in its infancy, but it is equally clear that it could go somewhere significant. There will always be the introverted, self-regarding blogs and that's fine, but many, like John Jones's The Edinburgh Blog, have higher ambitions. "I guess I hope it could inspire some readers to believe they can create local, targeted content which can benefit the community they live in," says Jones. "Too many blogs lack focus and lack creators who have the drive and determination to turn their blog into something useful, something real."