As Iain Dale explained about his own system: I mark each blog out of ten on the following 10 areas: design; frequency of posting; writing ability; personality; comment; humour; range; interaction; popularity; independence of thought. This generates a mark out of 100.
James Higham uses 9 of these, sometimes combined, adds a few others and posits these as the criteria of a great blog:
1] fearless independence of thought and the ability to come out with new ideas and new perspectives on a more or less regular basis, in a spirit of genuine enquiry, unfettered by dogma, party line, prejudice or one issue obsession e.g. the 4th player, managerialism or flat rate tax; the ability to attack both sides equally and the opposite – to praise both sides equally;
2] enormous range of inclusion – either every possible aspect and ramification in a one issue blog or global scope in the issues covered in most fields, the only criteria being whether they are a] important b] interesting;
3] sheer writing ability – the ability to string words and phrases together with hardly an error [or typo], the blogger clearly educated at a reasonably high level in the language he or she was born into;
4] authority behind the writing – bona fides based on obvious [to the reader] ability in the field, life experience, a wide range of reading about the topic but not on formal qualifications or position;
5] personality & humour – this also includes ‘niceness’ or the ability to attack targets tongue in cheek, with dignity and wry humour. Quirkiness is not essential but it’s a sign the writer doesn’t take himself or his position too seriously;
6] innovative blog design as a reader service – not only pretty headers and nice colours but providing one touch information in the sidebars, accessible to readers - treating the blog as a service to the reader, rather than as a forum for one’s own opinions;
7] major works of substance from time to time – a blogger must display his bona fides by producing something substantial in fine detail, academically sound and capable of defence. This doesn’t necessarily mean a tome but does mean a long piece from time to time, on a worthy subject. This then needs to be followed through and the theme will appear in subsequent posts.
8] frequency of posting and consistency of identifiable style – maintaining the service with no huge experimental changes and giving the reader what he or she comes for over and over and over;
9] willingness to tweak - constantly working to improve everything from layout to comment, never resting on one’s laurels and saying ‘here’s my package – take it or leave it’ but rather listening, reading, learning and most importantly, growing as a blogger. A smug blog is a dead blog;
10] interaction with other bloggers and readers, comment of value on the issues of the day, mutual support e.g. this tagging business, e-mailing and well – interaction overall.
I’ve left ‘popularity’ off the list because I see it as a consequence rather than a criterion. If one takes care of the 10 criteria above, I feel popularity will come and I worry awfully about bloggers who are in it just for the stats. Mea culpa and the interesting thing is – once I stopped worrying [now I might view the stats once a day and sometimes not even that] and started concentrating on the product, the stats improved markedly anyway.
Update: Tiberius Gracchus, in his Ten-Meme-Never list, has done a similar sort of thing to this.