Ancestry.com and associated sites (Rootsweb and Find a Grave) were down for Monday, part of Tuesday and intermittently today due to a DDoS attack. Think of it like a bunch of people all dialing the same phone number at the same time (and keep dialing for a period of time) to make the lines busy, while people with legitimate reasons for calling aren’t able to get through.
There’s a post about it here.
The site is still slow, but should be back to regular service soon.
Type the web address in the box and hit Enter on your keyboard. The site sends a message to the site you are trying to access and tells you if it was successful or not.
At just before 5 p.m. June 18, Ancestry was down (still/again). Rootsweb was down, but Find a Grave was working.