For a EF-5 tornado it still should have been discuss alot more in the weather community but most chasers only care about what goes on in TX,OK,KS,NE and SD because that is where most chasers live. When it comes to OK I realy do not care much about the tornadoes there unless it is a historic event just because I do not live there. I am sure most chasers are the same way about IA because they do not live here. So it is not as inportant to them. If the Parkersburg tornado occured in Moore or Tulsa OK I bet we would have seen half of the members here discussing it.
Your comparisons with Moore or Tulsa aren't really good comparisons because those are major metro areas. If an EF-5 (or any tornado) ripped through a major metro area in any part of the country, I guarantee it will get a lot of attention. Look at the coverage regarding downtown Atlanta.
In a way, Parkersburg can be compared to a nighttime tornado. Nighttime tornadoes don't get a lot attention from the chase community, but that's because most people don't chase them...sort of like how most chasers (at least the ones on this site) rarely chase in Iowa because it's an area that's hard to reach for them. Yes, Greensburg was at night, but I've never seen a nighttime tornado documented like Greensburg, so it's something of an anomaly.
As previously mentioned, Greensburg has stayed in the news mainly because of the amount of destruction and the whole "going green" thing.
There were several noteworthy weather events this year in a very short amount of time, whereas Greensburg was pretty much the "only" show for quite awhile. Take a look at this timeline if you don't believe me.
May 22, 2008: Greely, CO
May 24, 2008: Hog farm video in Oklahoma
May 25, 2008: Parkersburg, IA
May 29, 2008: Kearney, NE (and the "Red Light Incident")
June 11, 2008: Little Sioux Boy Scout Camp, IA
Most of June 2008: Midwest flooding
Again, this is looking at it from the chasing side of things only. From the news side of things, 2007 was a "slow" news year in the U.S. In 2008, Parkersburg has fallen victim to the news of the presidential election. I mean, you would hardly know that we are in a war right now with all the news regarding the election and economy.