Now this is the point where techies miss the point. See, Gmail is a popular email system, and they serve masses who have no idea about the differences between jo.edoe@gmail.com , joe.doe@gmail.com and joedoe@gmail.com. The confusion arising from the use of the three would be far more complex to handle than the techies angered by the lack of use of the standard. 

In a company, it can be honoured, for a global provider , it is better to disregard it. 

Also most firms hose to ignore the use of a + in email addresses while Google honours it .