DoubleClick Inc., which sells advertising space on Internet sites, said it will buy closely held Opt-In Email.com with stock, in a deal that would let it offer e-mail marketing services. Other terms were not disclosed. DoubleClick plans to make Opt-In Email.com's services available to its clients next year. Opt-In Email.com, based in Boulder, Colo., has provided 1.3 billion e-mails for customers such as Mail.com Inc., ShopNow.com Inc. and Microsoft Corp. DoubleClick plans to use the services to offer publishers and advertisers a broader range of Internet services. "Opt-in" is the catch phrase for any permission-based marketing in which consumers agree to receive e-mail from companies. Shares of New York-based DoubleClick rose $10.38 to close at $170.44 on Nasdaq.