YSP offered the safety net of unlimited email contact and an optional physical meet-up with a local person, but found a greater market in young professionals and retirees.

YSP提供安全的交际网络，在其中人们可随意用电子邮件联系或者选择性地当地人会面，但却在年轻的专业人士和退休人士中发现了更大的市场。

youdao

This information is optional, but it's good practice to supply an email address if people want to reach you about the project.

这些信息是可选的，但提供电子邮件地址是比较实际的做法，因为人们可能希望与您取得联系。

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Real ID is an optional, richer level of identity, as it displays your real name, and can ONLY be shared by adding a friend through an email address.

实名ID是可选的，更高一级的身份，它显示你的真实姓名，并只能对被通过加电子邮箱的好友可见。

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Choosing to remain anonymous, they happily accept players worldwide and all cash-ins and cash-outs are denominated in bitcoin so no bank accounts are required and even your email address is optional.

FORBES: Bitcoin Casinos Release 2012 Earnings

The POS uses Breadcrumb Payments for processing, with deposits posting within 24 hours, and can be paired with a card swiper and optional printer (you can email receipts if you'd prefer).

ENGADGET

The app also features an optional upgrade service from Evoz that provides advanced monitoring, cry notifications via text or email, cry history information, and analysis of baby's crying and sleep patterns.

ENGADGET: Belkin WeMo Baby monitor lets you listen to Junior via an internet connection and an iOS device