The Viigo servers collect feeds for all subscribed channels and then provide a stream of just new articles to our users. Viigo then logs and sends out only the delta of new information to users. That way Viigo is not calling a full RSS feed over and over again as do desktop RSS readers for which data costs aren't an issue. Furthermore, Viigo compresses the content on the way to the client to further improve data efficiency and minimize data costs.
The implication of this is that Viigo collects over 100K unique feeds on our servers and delivers millions of articles per day to tens of thousands of users. It is the feed collection cycle time that may cause delays in updates. The Viigo servers collect feeds according to popularity. The most popular feeds that are subscribed to by 99% of Viigo users are collected every few minutes. Feeds subscribed to less frequently can take a couple of hours to collect depending on the loads on the server.
When you update channels manually, Viigo bypasses this collector queue and retrieves the most recent information on demand.
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