It's been hard not to notice the recently growing roster of digital media/broadband video executives who are either leaving their jobs or jumping to other companies.

Among the many recent changes:

• Bill Day (moved to CEO, ScanScout from Chief Media Officer, Marchex)
• Ned Desmond (leaving as President, Time, Inc Interactive)
• Tony Fadell (leaving as SVP, iPod Division, Apple)
• Karin Gilford (moved to SVP, Fancast/Comcast from VP/GM, Yahoo Entertainment)
• Bob Greene (left as EVP, Advanced Services, Starz)
• Kevin Johnson (moved to CEO, Juniper Networks from President, Platforms & Services Division, Microsoft)
• George Kliavkoff (leaving as Chief Digital Officer, NBCU)
• Michael Mathieu (moved to CEO, YuMe from President, Freedom Communications Internet Division)
• Scott Moore (leaving as SVP, Media Group, Yahoo)
• Herb Scannell (moved from CEO to Executive Chairman, Next New Networks)
• David Verklin (moved to CEO, Canoe Ventures from CEO, Aegis Media Americas)

Of course there are many more as well.

There's no blanket explanation for all of this movement. Senior executives - particularly those with strong track records in unchartered territory like digital media and broadband video - are always in demand by competitors. And established companies who can't execute or who are losing altitude in their core businesses become fertile ground for executive recruiters. Then there are always personal reasons for causing executive change (family matters, geographic restrictions, etc.).

The whole digital media and broadband space is extremely dynamic. Major incumbents continue to struggle with defining their strategies and how to organize themselves properly to execute. The financial meltdown has caused huge profit pressure, prompting operational streamlining.