Google's testing of RSS ads is not its only foray into the possibilities afforded by new syndication technology, ClickZ reports. Some users of Gmail, Google's web-based email client, have this week been testing Gmail Clips, an RSS feed aggregation feature allowing them to subscribe to content from blogs or other sites. Advertising seems a part of the design, with the Clips area displaying headlines from subscribed feeds or relevant sponsored links.

Users can scroll through the clips and link to the source page. Users can select suggested feeds, located in the Clips area at the top of their inboxes, or add links of their own.

For some time, Yahoo has been offering ad-supported RSS aggregation through My Yahoo, and MSN has said it would be launching an aggregator of its own.