The most notable aspect of the OB Pier, aside from its odd Y shape and its incredible reach into deep water, is just how clean it is. Now, I write this as a lifelong resident of San Diego, one who grew up only five miles from the OB Pier and who has only just today ventured out onto it. The fact that OB Pier is so clean is made remarkable by the fact that OB itself is decidedly not clean, as any San Diegan can tell you.
In fact, on our walk to the pier, we stepped over four sleeping homeless people and one sleeping homeless mastiff. We also heard eight conversations about drugs and saw some woman doing meditation or yoga publicly on a patch of grass. There was acoustic guitar playing and people permanently bereft of shoes. Unless I am mistaken, these are people who usually congregate in dirty areas. I do not believe these people cause the dirt, but that the dirt is a more earthy and natural substrate upon which these yoga-people, acoustic-guitar-players, and barefeeters can satisfactorily engage in drug use.
For a point of comparison, as a place composed of people who use drugs because they are freed from financial concerns, OB is everything its northern neighbor, PB, is not: a dirty, unwashed, and still interesting place.
While OB is notoriously grungy, its pier is not so and the reasons for this are not obvious. It could be that the pier is clean because it's close enough to the water to be sometimes washed by it. Maybe OBites are simply proud of their pier and so they work hard to keep it a pleasant and unobstructed place to get unbelievably high.
Overall, it is a very nice pier, even if there is no jumping or diving allowed.
Conclusion: Surprisingly Clean