New ad formats under beta? Or specialized for a very popular site?

[Grinler]

Certain sites I visit have Google ad formats that do
not appear to be available to most publishers? Are these formats available to these sites because they are in beta and being tested, are they custom made for them due to the popularity of these sites?

Some sites that I have noticed had these types of google ads are ones like digg or sourceforge.

[ken_b]

Are these formats available to these sites because they are in beta and being tested,

are they custom made for them due to the popularity of these sites?

Could be either of those, but since you mention sites the size of digg or sourceforge they are probably premium partners. Premium partners need to produce 20,000,000 page views per month if I recall right.