Over-the-top keyword stuffing on a site is a big no-no when it comes to SEO, but what about using <..comment..> tags in the html. It doesnt show up on the page, but would it be seen as spamming if used too often?
It is a heck of a gamble to take, it is clearly not there for the users or visitor so it has to be for bots. This sort of thing can easily be picked up. If your site was every to receive a manual review it would certainly be questionable.
Surely that means 'text' (i.e. the picture of a word) in the graphic itself
Yes, like the webmasterworld.com logo text in the top left corner of this page.
I wouldn't bother using them. They just act as a big red flag for search engines. Wouldn't look good under a manual review!
Don't bother then, but the quote I posted above is what Google actually advises us to do. They don't have a problem with it. They actually say that we should do this and in my experience it works. I think that it is a flag for the search engines but not a red one (and Google don't do manual reviews).