1971: Dear user, You cannot have more than 10,000 records. If we increased the maximum in the data base schema, we'd have to modify half of our software. Sorry, IT.

1981: Dear user, You cannot have more than 10,000 records. Our software vendor set this limit and we don't have the source code. Sorry, IT.

1991: Dear user, You cannot have more than 10,000 records. We don't have enough room in our budget for more hard disk. Sorry, IT.

2001: Dear user, You cannot have more than 10,000 records. Our network traffic is so high that we had to set arbitrary limits. Sorry, IT.

2011: Dear user, You cannot have more than 10,000 records. The internet is full. Sorry, Google.

[EDIT: Replaced "contacts" with "records" 5 times. The general case causes less confusion. Thank you, juiceandjuice.]