If my memory is correct, when they merged it back into the Live brand they also downgraded the standard storage space to 7GB. If you logged in sometime during the transition period or clicked on a special link that they sent out in an email you got to preserve your 25GB of storage.
It wasn't a login, you had to have at least one file on your skydrive before the recent merge to keep the 25GB.
Effectively you now can get e.g. 45GB for 10$ a year. Dropbox' old 50GB for 10$ a month plan was a joke in comparison.
They launched with 25 gigs but that was only a short term promotion at the start of this year. 7 gigs is their standard free offering. Anyone who signed up during the promotion period gets to keep 25 gigs free though of course.