It seems Sky broadband customers are the latest to suffer congestion, though it is confined to a relatively small number of exchanges out of the total number they have unbundled across the UK.
The problems exhibit themselves as a rise in latency affecting online gaming, and problems with streaming video, in the most extreme cases content rich websites may also slow down. The issue is not with the core Sky fibre network, but appears to be affecting areas where exchanges may be daisy-chained as a means of linking them back to the core network.
The list of exchanges was last updated on the 1st March, with resolution dates for when more capacity will be made at each exchange.
Individual exchanges suffering congestion is nothing new, it happens to BT Wholesale exchanges regularly, as the number of broadband customers and usage levels increase. So assuming Sky meet the upgrade dates there is no great cause for panic. What has probably happened is that use of services like Netflix and Sky Anytime+ has accelerated the bandwidth demand curve, meaning that previously planned upgrades did not happen soon enough.