The series finale of Lost drew the show's best ratings in more than two years, but it didn't draw in a ton of viewers who weren't already watching.
The heavily serialized nature of "Lost" probably kept away a fair number of people who had dropped out earlier in the show's run or hadn't seen the show before. (And although the finale focused most heavily on characters who had been with the show from early on, it still would have produced some head-scratchers for casual fans.)
The 2 1/2-hour finale drew "Lost's" biggest audience since early in Season 4, averaging 13.5 million viewers and a 5.8 rating among adults 18-49 in the overnight ratings (its numbers will probably grow some when seven-day DVR numbers are figured in). It was also the show's highest-rated season finale since the Season 3 ender in 2007.
By all measures "Lost" was Sunday's (May 23) highest-rated show, but it didn't draw a great deal more viewers than it normally does. For the season "Lost" is averaging 11.55 million viewers per episode (including seven-day DVR viewing) and a 5.1 in the 18-49 demographic, so the finale provided about a 15 percent bump in total viewers over a typical episode and a 12 percent improvement in the demo.
In contrast, the "ER" finale last year (16.4 million viewers) improved by more than 40 percent over its prior season average of a little over 10 million viewers. It had been on the air for 15 years, however, and was less difficult for former viewers to pick up for the last episode.