This is something I should have read more carefully.

<<How do I properly attribute a Creative Commons licensed work?

If you are using a work licensed under one of our core licenses (Attribution, Attribution-ShareAlike, Attribution-NonCommercial-ShareAlike, Attribution-NonCommerical, Attribution-NoDerivatives, Attribution-NonCommercial-NoDerivatives (this is the same as the Music Sharing license)) or under our Developing Nations license, then the proper way of accrediting your use of a work when you're making a verbatim use is: (1) to keep intact any copyright notices for the Work; (2) credit the author, licensor and/or other parties (such as a wiki or journal) in the manner they specify; (3) the title of the Work; and (4) the Uniform Resource Identifier for the work if specified by the author and/or licensor.

You also need to provide the Uniform Resource Locator for the Creative Commons license that applies to the work, together with each copy of the work that you make available. >>
http://wiki.creativecommons.org/FAQ

So, basically, if you post a CC-licensed photo on a blog, you need to include:
* the license + a link to the license
* the title of the photo (what if you can't find any?)
* the author
* a link to the original work
* how you modified the photo (does resizing/cropping a photo is considered modifying it?)

Most of the time, when I posted CC photos from Flickr, I included the license (no link) and a link to the Flickr page + the author ID. Does this mean I broke the license?

Technically, it looks like it. I guess you're supposed to link to the actual license so that visitors to your site who may want to re-use the same image understand exactly how it's licensed.

Would the rules be different if you were hot-linking to the Flickr-hosted image rather than copying the image to your server? (Is hot-linking to a fully copyrighted image without attribution legal?)

True, but what if you link to a Flickr page that contains the title, the author, his profile, the license etc?

The FAQ is not the CC license an author uses, so if you want a precise answer you need to look only at the CC license itself – its human-readable form as well as it's legal wording – and nowhere else. The CC license, at least mine, reads (http://creativecommons.org/licenses/by-nc/2.5/):

"Attribution. You must attribute the work in the manner specified by the author or licensor."

(E.g. if the author provides their name as "John123" then you need to credit him as John123.)

And:

"For any reuse or distribution, you must make clear to others the license terms of this work."

(E.g. when the author has an Attribution-Non-Commercial license then you need to reference this in some way.)

Furthermore, the legalese reads:

<<You must keep intact all copyright notices for the Work and provide, reasonable to the medium or means You are utilizing: (i) the name of Original Author (or pseudonym, if applicable) if supplied, and/or (ii) if the Original Author and/or Licensor designate another party or parties (e.g. a sponsor institute, publishing entity, journal) for attribution in Licensor's copyright notice, terms of service or by other reasonable means, the name of such party or parties; the title of the Work if supplied;>>

... and it goes on to say that ...

<<... to the extent reasonably practicable, the Uniform Resource Identifier, if any, that Licensor specifies to be associated with the Work, unless such URI does not refer to the copyright notice or licensing information for the Work; and in the case of a Derivative Work, a credit identifying the use of the Work in the Derivative Work (e.g., "French translation of the Work by Original Author," or "Screenplay based on original Work by Original Author"). Such credit may be implemented in any reasonable manner; provided, however, that in the case of a Derivative Work or Collective Work, at a minimum such credit will appear where any other comparable authorship credit appears and in a manner at least as prominent as such other comparable authorship credit.>>

Note that the legalese specifically says "reasonable to the medium" and "to the extent reasonably practicable". This in my interpretation means that if you think it's unreasonable to the medium to reference a photo's title, then you don't have to do it, and if you think it's unpractical to name the exact change you made with a derivative work, then you don't need to name it.

What I do when using CC-licensed work here is to name the author (with a link to the work), and name the license (with a link to the license). But I think there are exceptions to every rule...