Domain name holding pages link back, good or bad?

[spiralsites]

We are a web design and hosting company

http://www.spiralsites.com

But when we register domains for clients, or they take email only or a name is parked we have it using a holding page  which can be seen as follows:

http://www.jcevents.co.uk/

is this a good thing?

Bad thing?

Could it would it should it benefit our rankings?

Should we do more to make it look less like our main site and actually try to use it better to help rank our other services pages?

[SEO5Team]

Matt Cutts confirmed that Google has a "parked domain detector" that filters out parked domains thereby eliminating any SEO benefits. Matt Cutts Video link 

[SEM-Freak]

Links from a holding page won't help. Drop the concept. Forget short-cuts. Invest in decent content. Push that content and reap the rewards