Webmail (or Web-based email) is used to describe two things. One use of the word is to describe a Webmail client: an email client implemented as a web application accessed via a web browser. This article focuses on this use of the term.

The other use of the word is to describe a Web-based email service: an email service offered through a web site (a webmail provider) such as Gmail, Yahoo! Mail, Hotmail and AOL Mail.[1] Practically every webmail provider offers email access using a webmail client, and many of them also offer email access by a desktop email client using standard email protocols, while many internet service providers provide a webmail client as part of the email service included in their internet service package.

As with any web application, webmail's main advantage over the use of a desktop email client is the ability to send and receive email anywhere from a web browser. Its main disadvantage is the need to be connected to the internet while using it (Gmail offers offline use of its webmail client through the installation of Gears.[2]). There exist also other software tools to integrate parts of the webmail functionality into the OS (e.g. creating messages directly from third party applications via MAPI).


Cloud Computing Email Services

• Google Apps - Reliable, secure web-based office tools for any size business Powerful, intuitive applications like Gmail, Google Calendar and Google Docs can help reduce your IT costs and help employees collaborate more effectively – all for just $50 per user per year.  Offers 50X more storage than industry average – 25GB of email storage per employee.
• PanTerra Networks - PanTerra Networks is the leading provider of cloud-based unified communications Software-as-a-Service (SaaS) solutions for small and medium sized enterprises. The Company’s WorldSmart solution is delivered from the cloud through a 100% browser-based UC client, eliminating any premise-deployed hardware or software. WorldSmart provides unified communication services for unlimited digital voice, video and fax, instant message, mobile text and email all with presence through a single user and administrative interface
• Cisco WebEx Mail - Cisco WebEx Mail reduces the burden of email management so IT can focus on strategic projects instead of routine tasks. Yet administrators remain fully in control through a web-based console, allowing them to adapt to ever-changing organizational needs. Cisco WebEx Mail includes advanced migration tools that simplify the migration process. The solution interoperates with existing email infrastructure as well as archiving and security solutions. This minimizes disruptions during the transition to a hosted email solution.
• Yahoo Zimbra - Zimbra is a next-generation collaboration server that provides organizations greater overall flexibility and simplicity with integrated email, contacts, calendaring, sharing and document management plus mobility and desktop synchronization to users on any computer. Zimbra Collaboration Suite’s advanced web application and server is built on open standards and technologies to deliver unparalleled per-user scalability and lower overall total cost-of–ownership (TCO).
• IBM LotusLive iNotes - LotusLive iNotes e-mail is a business-class messaging solution for everyone in your organization. Remote employees, retail workers and anyone who doesn’t work behind a desk will appreciate the easy access to company e-mail. With web-based e-mail, all of your employees will have real-time e-mail access from a Web browser and Internet connection. In addition to a web-based interface, all e-mail accounts are enabled with POP, authenticated SMTP and IMAP capabilities for use with e-mail clients such as Lotus Notes or Microsoft Outlook.
• ElasticEmail - Elastic email makes email sending easier for both the developer and business manager of a cloud application. Several cloud application platforms such as Windows Azure and Amazon EC2 do not provide an email delivery service and may even set limits on your email sending. Elastic Email provides direct email sending through a simple REST API. This means, instead of having to setup and configure an SMTP email server or service you can begin sending email immediately, without worry using one of the code samples found in our API Documentation.
• Microsoft Exchange Online - Microsoft Exchange Online is a web version of the ubiquitous on-premise e-mail client. Features include the ability to log on to your account and wipe your mobile phone of sensitive data if it’s lost or stolen. Some drawbacks: The program works best on Internet Explorer.
• AppTix - Apptix provides hosted communications services so you can focus on what’s important—growing your business. Apptix is the industry leader in business-class communications services—the proven company of choice for hosted Exchange email, business VoIP services, and SharePoint collaboration services to more than 20,000 organizations worldwide.
• AppRiver - AppRiver was founded in April of 2002 to provide simple, yet powerful email and web security solutions to businesses of any size. The company’s award-winning Secure Exchange Hosting simplifies the setup, provisioning and management of Microsoft Exchange by creating a complete managed service for administrators and end-users.
• RackSpace Email & Apps
• Rackspace Email provides all the benefits of a desktop program without being tied to the desktop. Log into Rackspace Email from your desktop, laptop, or mobile phone, and get instant access to email, calendars, contacts, tasks, and notes.