I do have something to say related to this topic, so I may as well bring it up here. WS: those buttons/banners are, in my opinion, not very good. The reason for that is that they do not fit, or have any relation to the current Furtopia site. With exception, perhaps, of the last button on that list. I personally feel that the Furtopia site on the whole could do with a BIG make-over. Currently, there is little style and continuity to the site, which I feel poorly represents the exceptional services Furtopia provides. When I look at other sites designed and maintained by everyday people, with everyday lives (I mean people that aren't like paid website designers), not necessrily furry sites, I realise how good they can look, and how good Furtopia could be. Actually, this forum is a very good example of this. The Furtopia forums have a consistent colour scheme and style. The format and layout globally matches. The graphics at the top give a stylish look and a focal point to each page.
Anyway, I bring this up not to be negative, but to help improve Furtopia for all current and future users. I feel once Furtopia has established a style scheme, then, link banners and buttons, following the style, could be produced, and used for link button/banner exchanges with other furry sites and services.
Talking about button size, I think that 90 (or 88) x 35 are common dimensions that are used. I think it would be worth investigating first, as obviously, when a site has a list of link buttons, they all want to be the same size - and you don't want the Furtopia one to be right out of place.
Again, I wish to state that these are my opinions, and that I wish this to be taken as constructive critisism, rather than a negative rant.