The Orioles currently (and shockingly) have the best record in baseball after 28 games, with a 19-9 record (the Nats could tie them with a win tonight). Since their last winning season in 1997, they have generally overperformed over the first 28 games, although they usually weren't exactly setting the world on fire.
The one notable exception was 2005, when they jumped out to a great start and were leading the division by 4 games on June 11 before beginning their decline. The 2005 collapse is undoubtedly on the minds of people connected with the Orioles, but this is a different type of team. In 2005, they were 16-7 in April despite being ranked #23 in ERA.
They overcame their awful pitching by scoring the most runs of any team. They had some talented hitters (Miguel Tejada, Melvin Mora, Javy Lopez), but that wasn't sustainable. Sure enough, their offense dropped off in May and they ended up 15th in runs scored at the end of the season.
This year, they are 2nd in ERA and 10th in runs scored. It is a more balanced attack, but the main concern has to be that their excellent pitching isn't sustainable (they were 27th in bullpen ERA last year, and 1st this year).
Can they sustain this (or stay somewhat close)? The bullpen seems solid, anchored by Jim Johnson, who has been lights out. They probably won't be the best, but it should remain a big improvement over previous years. The starting rotation won't scare anyone, and it remains to be seen if Jason Hammel can continue his torrid start.
Even if the Orioles don't make the playoffs, it's possible that they're like the 2001 Twins, who came out of nowhere with a bunch of young players but struggled to compete against the mighty Indians and trailed off as the season went along. They came back and won the division the next 3 years and remained a contender for years after.
They could also be the 2005 Orioles, but it doesn't feel that way, especially after seeing them win a 17 inning game at Fenway that they almost certainly would have lost at any other point since 1997.