Just the other day I needed to get hold of someone quickly, who I've connected with online but not yet in the 'real world'. They'd contacted me via email and needed some urgent info but hadn't left their contact details, perhaps assuming that I had them.
- They didn't have their contact details in their email - a simple email signature is a great way to provide these.
- Their online profiles have no contact information - if you don't want them in every profile, at least have them on your website.
- Their website is 'under construction' so no contact details there either.
- Include a phone number - not just a mobile.
- Provide an email address or a contact form.