A serious start up should not be using consumer grade DSL lines.

It's not about what lines your startup uses in the office. It's about what lines your customers have available to them.

Try getting something like a video streaming service running if your main consumer base has a traffic limit of several gigabytes a month.

True but thats a separate issue maybe you need to ask your MEP why they cut the budget for BB rollout to rural areas in the EU - But didn't cut the CAP subsidy for farmers

Define 'consumer grade' and 'serious startup'

Code is not big, other resources like images, etc, may take more space, but that's often not an issue.

More importantly, 'consumer grade DSL' may be all that's available depending on the location.

Of course, the website is not being served from there.

You can't get business ADSL, SDSL or a leased line in Germany I woudl be surprised if that is the case.

In fact knowing Germany I am not surprised that using a consumer line for business is not breaking some rule.

Of course you can get business ADSL, SDSL or a leased line in Germany. It's just a lot more expensive (on the other hand you often get a much better service).

That was my point