Jumping on Point

Basically, a point in an ongoing series or a series in a Shared Universe that exists primarily to provide a place for new readers to begin with without needing to know the entire history. This is especially common in Comic Books and other media where Continuity Snarls are common.

If a point in a series, it will often restart the numbering -- instead of Spider-Man #237, it'll be Spider-Man volume 2 #1. It may be just after the resolution of a massive storyline, and it'll almost always show something similar to the general status quo of the series.

If a series in a Shared Universe, it may be set in an Alternate Universe or be about a new set of characters in the same universe, somewhat removed from the rest. It will often end up having its own Spin-Off, so that the new fanbase can diversify their reading without ever having to get fully immersed in the Universe.

When a whole new continuity is created, it's an Ultimate Universe.

Comicbooks

 * Two Thousand AD does one every so often in which every strip in the prog starts a new story. They are generally identified by the presence of Tharg on the cover.
 * The company 'Cross Gen' did that in one month for each and every single book.
 * It was meant to be an ongoing thing, but the publisher folded before they could do more. Between recap pages (with head shots of the cast) and generally avoiding Writing for the Trade, though, it was easier to jump into a CG story than those from other publishers.
 * DC Comics did one halfway through Countdown, when it was renamed Countdown to Final Crisis. The first issue under the new name consisted almost entirely of the Monitors discussing what had gone on in the previous 26 issues.
 * In The DCU, the "One Year Later" event was intended as a Jumping on Point for just about every title.
 * Runaways and its spin-off, Loners, have done this to an extent. Wolverine doesn't even get his standard cameo until the 10th issue of the second volume. Furthermore, interaction with most of the Marvel Universe is somewhat justified. Basically, it's explained that The Pride had muscled all the other villains off the West Coast, and kept crime orderly so the superheroes didn't step in.
 * With their defeat in volume 1, the West Coast now seems a likely setting for more Runaways spin-offs, built around new characters and formerly B-string superheroes whose origins can be covered quickly to the uninitiated, who attempt to help the Runaways fight the villains attempting to take over the West Coast with the power vacuum after the Pride's defeat. (On the other hand, the California-based Initiative spin-off "The Order mentions none of this.)
 * Welcome to Tranquility has a group of retired superheroes and villains and their families living in a community isolated from the rest of the Wildstorm Universe. They even have their own special name for supers, "Maxis". The isolation is explained more as the series progresses.
 * Issue 11 of Zot, according to the author. Very few plot points are all that confusing, and those that are will usually be explained away in later issues.
 * DC Comics did this on a massive scale, cancelling all their titles and launching 52 new ones (most of them are just new volumes in old titles) with the intention of drawing in new readers through having a single clear starting point for all of their books. So far it seems to have worked.

Live Action TV

 * The 2005 season of Doctor Who, which revived the show after a long hiatus, keeps the continuity of the old seasons (or at least as much continuity as there can be in a show about time travel), but does not require having seen the old seasons to make sense, so it is considered a jumping on point for the series.
 * Another point was in 2010 when Matt Smith took over the role from David Tennant -- they wrapped up old plotlines and discarded most of the supporting and recurring cast.
 * Stargate SG-1, the beginning of Season 9 was a Jumping On point. With the eight-season long story of the Goa'uld and the Replicators pretty much wrapped up, a brand new Big Bad and a significantly changed Five-Man Band was practically a new series. Was supposed to be, but Sci Fi wanted The Longest Running Science Fiction Show on American TV. Then they promptly cancelled it once they reached that benchmark.

Toys

 * Bionicle attempted this a handful of times. When the first story arc ("Chronicles") was done in 2003, after a two year Flash Back ("Adventures"), the story took a new turn, and in accordance with this, they restarted the comic numbering and created a new "Legends" umbrella title for the books. However the story was still set in the same universe and continued the same general plot, which eventually went messy. The folks at LEGO decided that a more radical push of the restart button was needed, so the quickly set up a whole new world with new rules, new characters and a new backstory. In half a year's worth of plot, this idea went out the window, the two storylines got tied together firmly, and a year later, LEGO ended the line.

Video Games

 * Resident Evil 4 jumps forward six years, starting what is essentially a brand-new storyline. Leon recounts the history of the previous games in his Opening Narration. There are a few elements from the previous games, but they're not really necessary to follow the story.

Web Original

 * Whenever a Global Guardians PBEM Universe campaign recruited a new player, the game master generally used one of these to give them a level playing field to begin with rather than forcing them to hit the ground running mid-adventure. They usually took the form of a side-story that would introduce the new guy to the veterans, and vice versa, and bring the new guy up to speed. After that, the entire group would return to the original storyline.
 * Red Panda Adventures does this at the beginning of each season.