To acquire users, online services employ a variety of means. Among the most common:
- to invite via email and chat
- ideally, using the email address and chat address list of the user themselves, e.g. Facebook and Flixster recognize yahoo.com email, hotmail.com email and gmail.com email to invite anyone you've corresponded with - increasing reach radically
- share files using applications with local data drive access, as in P2P like emule and bittorrent; services that share playlists like imeem, share bookmarks like Digg or open tag systems or share social networks like Facebook must consult local data, not just that already online
- to share via email and chat, e.g. aim:goIM
- allow anyone to embed content especially embed content in blogs as an alternative to Atom feeds
- test signups using A/B tests - using one headline versus another can create a 5x difference in signup percentages - people respond to different value propositions, e.g. "focus on Free versus Sharing versus MySpace versus whatever Web 2.0 proposition you have" says Andrew Chen. Tools like Survey Monkey or Offermatica let you quickly create pages, drive web traffic to it, and see how people respond to differences in layout, headlines, copy, etc.. A long-tail version of this for bloggers may soon emerge to make this very easy.
- buy adwords effectively: "you want to buy literally 10s of thousands of keywords" says Chen, i.e. not just "music" but also music genres, artist names, CD names, etc.. keywords must be drawn from user-generated content, e.g. in fashion the brands, celebrity names, fashion genres, etc.. To compare shopping options isn't easy and requires mastery of keyword combinations, tested for the best ROI. A Google referral list tells you what keywords people already use to find you.
- viral referrals are useful in invite-only services, but even those like LinkedIn help manage contacts - generating more email and invitations, e.g. when you defer to experts. Chen says that "one interesting vector on MySpace, from people I've interviewed, is oftentimes their experienced friends set up their accounts so that they have a way to keep in touch more easily." It may be helpful to track people who are not users but have been mention/invite/recommended or otherwise had their names volunteered
- SEO and landing pages optimized for new users who come from search engines deserve intense attention since there are always more of them than the core users; More landing pages is better, even if not user-accessible - but titles must be carefully managed, and URIs, to avoid confusing or annoying users; To add links, syndicate content and otherwise customize the page to the user's query makes you a specialized search engine; Wikipedia for instance is often used as a reliable way to find some credible out-links on practically any topic; The sheer size of the GFDL corpus provides the landing pages
- Use of RSS feeds and email subscriptions also creates stickiness, especially if they are used for everything - permitting people to disengage and come back weeks or months later. People often forward email so every email should encourage, or even reward, viral referrals.
- user drag, that is, loss of users from landing to signup, can be significant; all data on link transit must be kept so that it's clear which are the popular link paths; any barrier whatsoever to signing up is bad and often requires tests, at many different stages. Web form rejections like a short password or filled field require an immediately alert with no page refresh. If you wait until they submit, you may lose them entirely. A multi-step signup should be separated to keep optional material last - ideally not until they've signed up, are doing something, and see utility in sharing the data