News aggregator Feedly and online note-taking software Evernote have both suffered Distributed Denial of Service attacks in the last few days, restricting access for users.
Earlier today, Feedly claimed in a blog post that it was being held to ransom by cyber attackers. "Criminals are attacking Feedly with a distributed denial of service attack (DDoS).
"The attacker is trying to extort us money to make it stop. We refused to give in and are working with our network providers to mitigate the attack as best as we can.
We are working in parallel with other victims of the same group and with law enforcement," it added.
A similar attack hit Evernote on Tuesday 10 June, though it is as yet unclear whether the two incidents are linked.
Users of the service were temporarily unable to synchronise notes across devices after the issue began.
Feedly has informed users their data is safe and assured them that work is being done to resolve the issue.
Evernote has experienced this type of problem before, with hackers accessing user names, email addresses and passwords of users in 2013.
This attack does not appear to pose the same level of risk to users' data, however, with DDoS attacks caused instead by servers being overloaded with targeted data send by thousands of computers.
Spokeswoman Rhonda Scott told the BBC: "We continue to mitigate the effects of the attack, but have successfully returned Evernote to service. As is the nature of DDoS attacks, there was no data loss, and no accounts were compromised."
