I'm not sure if paper-based invitations are still used a lot these days as most of my life (work and social - and there's very little of the latter) is based online, but if you have a big party or event coming up and you're thinking about what type of invitations you'll use with environmental impact in mind; you can opt for recycled paper - or perhaps consider virtual invitations such as Pingg provides.

Pingg is a free and ad-free electronic invitation service that provides a wide rang of stylish invitation designs - these are more than just ecards. Pingg invitations can include video, your own photos and maps - a particularly useful idea to help your guests find their way. Event specific functionality including gift registries and fundraising features are also available. 

Another interesting aspect of the service is SurroundSend (an additional fee). For some of your guests, electronic invitations may just not be practical for whatever reason, so Pingg offers print invitations and SMS options as well. Additionally, the service can also post event information and send messages to Facebook profiles.

Pingg has a nice range of free invitation designs and themes, but you can also gain access to 2 million+ unique and original designs at an additional cost.

If you're getting married soon and have the environment as close to your heart as you do your beloved, the Pingg service might be a great addition to your green wedding! :).