With a purpose of avoiding "More details here" style links that do not provide any information in the link itself, what styles are common/popular/suggested?
A good example case (with bold as the potential link):
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
And so on. What advantages or disadvantages are known?
If you think of hyperlinks as text designed to attract attention, then it quickly becomes apparent that you should hyperlink text that could, on its own, be seen as the key point you're trying to take from the text you're linking to. From a user perspective, whenever you're reading text that has underlined text or text in a different colour, it's almost instinctive to scan through these. Therefore, "John Q claims pigs can fly" is likely your best bet.
However, there is another point to make, unrelated to writing, and that has to do with the SEO implications of the text itself. If you link with the word claims, this says absolutely nothing to search engines about the text you are linking to. pigs can fly however, indicates quite clearly what the text you're linking to is about, and this adds weight to those keywords for that site to search engines.
Admittedly, the advantage of such linking is often in favour of the site you're linking to, not always your own, but when you're interlinking to posts on your own website, this can have an impact on how search engines see your site and content e.g. "In an earlier post, I discussed how pigs can fly, but ..."
As noted in Aedia's answer, WCAG 2.0 accessibility guidelines recommend that the linked text should described the purpose of the link.
In your example, I would favour linking the full sentence:
John Q. claims that pigs can fly.
There are couple of other aspects to consider:
Certainly inline links are popular in blogs, but as an alternative you can consider explicitly mentioning the source of the link, at the cost of slightly interrupting the flow of your piece:
John Q. claims that pigs can fly (see Flights of Fantasy, Porcine News, Issue 3.).
If you do decide to stick with inline links, users' expectations will be shaped by the consistency with which you link to various sources. Fair warning of potentially undesirable links should be given. For example, your readers may expect links to explicit content, or links to large PDFs, to be flagged, depending on where your content is appearing.
You can find a good example of inline linking in BBC sports journalist Phil McNulty's blog. His blog targets a mainstream public audience. He uses long link anchors that describe the content of link destinations, and typically links to other sports journalism articles on the BBC website or from national newspapers.
A style that conforms to the WCAG 2.0 accessibility guidelines would ensure the link text describes the purpose of the link. You might use simply the title of the page you're linking to, or part of the title.
Another way to evaluate: If the link is read out of context, does it make sense? As @Craig Sefton mentions, this has SEO implications, but it's also what users skimming will notice and it's the way users with screen-reading software will navigate quickly (by jumping to a list of links). For example, John Q. claims that pigs can fly would make sense, or even claims that pigs can fly, but John Q. may be interpreted as something else (a page about John, perhaps).
I struggle with this one all the time. A lot depends on context, but in general I'd go for clarity and usability. I wouldn't use the name, as that to me would imply a link referencing the person rather than the claim. So I'd go with either:
John Q. claims that pigs can fly.
John Q. claims that pigs can fly.
Longer links are more user friendly than short, single word links. Unless you have number of links that all fall one after the other, in which case I like to keep the links separated by static words to better distinguish them. If you have too many links to do that, I'd suggest rewriting that section.
A link to the name is generally expected to link to the person, not to an article.
I generally agree with @Craig Sefton, except that I would make "claims that pigs can fly" the link and not just "pigs can fly". It's a claim (by John Q), not a fact; "pigs can fly" could link to, say, a wikipedia page explaining the idiom. It would also be reasonable style, though perhaps too short for good UI, to just link "claims".
In general, think about what is on the other end of the link -- the person? the fact in question? the discussion? Then link accordingly. I can imagine cases where your example would actually have three links -- one for John, one for his claim, and one for airborne pigs.
