It's up to the author to specify. For most wikipedia text, you need to link back to the original article or a copy of the article or include a list of the major authors.
On the other hand, StackExchange is more onerous - they require a link to SX, a link to each author, each author's name, links to each author's profile, and a text blurb indicating that the content is from SO. Oh, and no "nofollow" links, or JS tricks - they want the google juice.
You also need to ensure that derivative work is also CC, if there is a -SA clause (which I think is the case for both wikipedia and SX.
It should all be there in the TOS page.
If they author/site doesn't say, just link back to them, and include a short blurb (i.e. "by <username> at <website>". Really, that's likely to be all they want. If they cared about the legalities, they probably include them in the TOS. Or email them, asking for clarification.
For Wikipedia, apparently someone did their homework: the disclaimer under the edit box says "You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license."
SO's insistence on non-obfuscated links doesn't make much sense to me, though. Users retain copyright to the content they submit to SO, so it's them, not SO, who say which attribution they would like. SO could require some sort of attribution to be sufficient (like Wikipedia does), but users are free to say that they accept any sort of attribution besides that, even one which does not credit SO at all.
If author does not specify the details, just add a line saying something like: "Icon (photo, music, whatever) credit: John Doe, www.example.com" to your about page.
If you want to help the author a bit more, especially on the web, link to the specific page and provide a description, e.g.: "[Yellow Monkey Icon] (links to the icon page), (c)/by John Doe, used under a Creative Commons Attribution license". This helps with SEO.
If you're making a derivative work, say so.
At least that's what I suggest for my CC-BY works.
This is certainly the sensible way. But with legal contracts it's not enough to be sensible. The author is supposed to specify. The times I've contacted authors to ask about their desired attribution they've never contacted me back (only about half-a-dozen times now).
Actually, what I really need is a VerbProject. What's the universal symbol for "Invite your friends"? How about "Like"? Web apps are more full of verbs than there are nouns, but we use icons of objects as substitute for verbs. like an envelope for "send mail" and a floppy disk for "save"
I've been using a few of them lately; they're great. However, I wish they would expand their wonderful noun project to include verbs and adjectives and more. (Yes, it looks like they take the noun part rather serious.)
Small suggestion - don't start searching until the user has stopped typing for a short period (or if you're doing that already, increase the time-out). If I'm typing 'house', I don't need search results for 'h', 'ho', 'hou', etc., and since the site is running slow at the moment, it seems to get a bit confused when multiple result sets come back.
I used these before on a travel site - fantastic. Some of the icons are a bit too over-worked (ie. they don't work well small, and they're a little too detailed) but overall, a huge set of icons really well designed. Only issue I had with the site (a while back) was couldn't find a big ZIP download of all icons, or PNG files. Had to go to some other big creepy download site for that. Weird.
Yes, but PNGs will be easier to deal with than SVG and webfonts. I guess SVG give you the flexibility of turning them into high-fidelity versions of whatever you want. I regularly use nounproject SVGs to create 'icons' in Microsoft's vector XAML format.
Wanted to give you a heads^ that there was some lagging during homepage load and during icon (file) zip: 'noun_project_705.svg' downloading. I'm on MacBook Pro OS X Version 10.6.8 using Chrome (and the apps I am controlling in other Chrome tabs are cruising). Maybe there's some versioning-optimization fixes you could look into - or maybe it's me. I'm running at full wiFi connectivity (and AirPort bars) at the Sandbox Suites near Union. So I thought I'd at least drop you my observation as to see if I could help. Overall though - sleek work, I find comfort when controlling your app.
An impressive suite of icons in a nice minimalist format. But...I guess looking at a large number of these, linguistic expressions seem to be less complex per concept than the iconographic equivalents.
Perhaps you could allow feedback on icons?
A number of them don't conjure for me the thing they're supposed to. For example, 'mummy' is definitely not what comes to mind when I see the 'mummy' icon. The icon doesn't really look like anything in particular to me; I find it just gives of a slightly weird vibe. Or the 'golf' icon - the club looks more like a hockey stick to me.
I'm on a laptop with Internet explorer 8 and is getting the message that "Internet explorer does not support the NounProject", and later down on the page "Currently, Internet explorer is the only browser that cannot display the format that is best suited for this site".
Does anyone with access to the site, know what this technology / format is, that IE 8 doesn't support?