What is the pros and cons of a marketplace website like houzz.com, zillow.com and trulia.com where users send mail to professional without logging in?

It really depends on your mission and from where you intend to drive revenues.

Asking a guest to create an account and log in in order to send an email to your customers could be seen as a stumbling block.

The more you can encourage visitors to reach out to your customers, the more your customers will have a great experience,

On the other hand, you have to make sure you all the security measures in place so your customers do not get spammed through your site.

Give me a call to discuss further. I offer a free initial call to first time clients. Use this link:

https://clarity.fm/kevinmccarthy/FreeConsult

Good things : 1. It may lead to revenue generation and make you active to get jobs and business without any restrictions.

Bad things: 1. Some times users become fade up by getting unwanted calls and email notifications.

Conclusive Points: I think everything should be in restrictive way so clients should be happy on marketplace websites.

You may check my marketplace

http://www.douleutaras.gr/

Vineet Verma