A common feature in blog software is a Blogroll, this is a list of links to blogs which are associated in some way with the blog in question – most commonly it’s a list of blogs run by friends of the blogger in question.
Now in the case of friends with very similar interests (IE same religious and political beliefs, sexual preferences, hobbies, etc) this wouldn’t cause a problem. In the case of commercial blogs it also will work well (EG Google runs a large number of blogs which contain links to all the rest – they may not interest all readers but should be expected not to offend any).
In the case of personal blogs where people don’t always have the same interests there is scope for problems. A link to the main page of a blog is an unconditional recommendation for the blog. There are not many of my friends who I share that much in common with that I would be prepared to give such a recommendation for a frank personal blog, and for those few I am unwilling to do so as it generates social pressure to include others. Some of my friends who didn’t get listed in my blogroll would probably get offended, even though it’s only the occasional post that I strongly disagree with which would make me refrain from such a listing.
I appreciate it when people add me to their blogroll, but don’t have any expectation that the listing will remain (I’m not going to get offended if someone changes their criteria for listing and removes my entry). But I consider it an equal compliment when someone cites one of my blog posts as a reference and recommends that other people read it. Citing an individual post has the advantage (for the person citing the post) they are specifically not recommending my entire blog. For example if you recommend one of my posts about Linux and one of your readers goes further into my site and is offended by my posts about politics then it’s not your issue. Tim Berners-Lee made an interesting point  “so readers, when they find something distasteful or unreliable, don’t just hit the back button once, they hit it twice“. I know that some people who would be interested in the technical Linux issues I write about don’t read my blog because they are offended by my political beliefs, I am not concerned about this – but I don’t expect that everyone who chooses to link to me will necessarily want to make the same trade-off.
When citing individual posts it’s possible to strongly agree with one post and strongly disagree with another by the same author.
Probably the best way of acknowledging your friends via blogging (if you choose to do so) would be to make an occasional links post which contains short positive recommendations to the best posts your friends wrote. If every month or two someone writes a links post (post which has little content, merely recommendations for other posts) which references your posts then you know that they like you (and you get a Technorati.com boost), so a blogroll entry hardly seems necessary. An additional benefit for giving such direct credit is that the person receiving the links will know what you consider to be their best work which will help them in their future writing.
I believe that adding this feature to common blogging software was a mistake. The small number of people who actually need this (such as Google) can create it via a HTML widget (IE writing raw HTML for the page – it’s really easy to do) and the rest of the population would be better off without it.