PTTAOLUTASF (permanently misspelled PTTAPUTASF in the comic) is an acronym for the "Paranormal Things That Are Of Little Use To Anyone Storage Facility." As the name implies, it is a building in which paranormal artifacts such as the Dewitchery Diamond are kept. It is first mentioned by Grace during "Sister, Part IV." 
PTTAOLUTASF is mentioned to be "a three hour trip by car" away from Moperville. The facility is so low-priority that there is only one elderly security guard that stays at the front of the building, and the windows don't even have glass; the building is so low priority that even Tedd apparently had enough security clearance there to enter it by just showing his ID. When Elliot went with Tedd, he had to climb through the window (since there was no glass, this was an easy task). They were caught by the security guard shortly after Ellen's departure, but were soon released after Mr. Verres came into contact with the guard. Part of the reason Tedd and Elliot were allowed to enter so readily may have been due to Sirleck bribing the security guard.
In (another?) retcon, Magus and Sirleck explains that it's actually a trap: it's a building on the middle of nowhere that appears to only have one guard at a time and is full of relatively useless or inert magic artifacts that give off just enough of a magic vibe to be sensed from outside. It lures thieves to it while distracting them from a better hidden facility that actually has important things in it; they are allowed to get in and take their time finding something to snag, and the real security system is triggered by trying to take artifacts out of the building or by trying to do anything to the guard.
Giant block of text Edit
Related "giant block of text" from EGS Main Story Comic for 2002-07-08 ("Elliot Is Probably Saying What Many Are Thinking"):
Alright, here we go. As you already know, Tedd's father works for the government. I was able to get access to certain information as a result of that, and have discovered an interesting little item that is being kept at the government's "Paranormal Things That Are of Little Use to Anyone Storage Facility", or PTTAPUTASF. There is an artifact kept at the PTTAPUTASF called the Dewitchery Diamond that dates back to medieval times. The Dewitchery Diamond is said to be able to separate someone who has been cursed with another form from that curse and return them to normal; all you have to do is touch it. Now, this is such a low priority government building that Tedd here actually has the clearance necessary to get in thanks to his father, but you can't legally accompany him and he can't legally remove the diamond for you to touch. Fortunately, however, the facility is so low priority that there appears to be only one elderly security guard who constantly guards the front of the building so once Tedd is inside he should be able to sneak you in through the back and get you to the diamond. There are only security cameras at the doors, which is good but you'll have to use a window to get in because of this. Afterwards, you just have to make it to the second floor, touch the diamond and get back out. I'll stay back here for a number of reasons including but not limited to the facts that the less people sneaking in the better, if I'm caught I might be taken away for testing or something, and someone needs to stay behind to feed Jeremy. Now PTTAPUTASF is out of town and is estimated to be a three-hour trip by car so it's best you leave ASAP.
There is a glass in window on EGS Main Story Comic for 2018-03-26 and previous page. There wasn't one on EGS Main Story Comic for 2002-08-08 ("Right Out That There Window"). This suggest the missing glass either wasn't deliberate and they fixed it in the year between those two strips, or maybe it just wasn't the same window.
- ↑ Post on Keenspot Forum, global post ID #1898706
- ↑ A possible explanation might be that the acronym substituted "Of Little Use" with "Pretty Useless".
- ↑ EGS Main Story Comic for 2002-07-08 ("Elliot is Probably Saying What Many Are Thinking")
- ↑ EGS Main Story Comic for 2002-12-27 ("Hungry Cat")
- ↑ EGS Main Story Comic for 2010-08-09
- ↑ EGS Main Story Comic for 2018-03-05
- ↑ danshive tumblr post ID 172277042737