Spam is an inevitable problem. It doesn't matter whether you publish your email address or not on a website, your data leaks out in so many other ways. Dealing firstly with providing an email address on a website...
It is good advice to protect your email address when using it on a website - for example only making it accessible once a visitor to your website as proved they are human. (This is called "Human Interactive Proof"). You will have no doubt seen some HIPs in action, for example when you have to decipher a barely legible code and type it into a field on a web form.
The second option is removing your email address all together, and instead providing a form on your website on which people can supply their details so that you can email/call them back. This poses two problems:
1) If you are asking people to provide their name, number and email address - that's personal data. Ergo, your website needs to be served over HTTPs (TLS) in order to safely collect it. This means either buying an SSL* Certificate and installing it on your site, or setting up HTTPs via LetsEncrypt.
2) If you try and contact someone via email when they've not emailed your first, some spam servers will pick it up as an unsolicited email and direct your email back to them directly to the spam folder.
Dealing with SPAM is challenging, although I'm surprised so much of it is getting through Yahoo's filters. As Interdit says, using an '@yahoo.com' email address doesn't exactly look professional either. With Google Aps for Business (or whatever it's now called) and Office365 etc. you can have a '@yourdomainname' email address. This is probably the easiest and quickest way of doing it, albeit inflexible.
Some web hosting packages will also offer email hosting - and they will offer N inclusive email addresses or, if you are lucky, unlimited email addresses/aliases. This means you can use different email addresses for different things and then you can at least see where the spam is coming from.
In terms of actually dealing with the spam there are several methods to be employed, either on the mail server (where your mail is hosted) or on the mail client (the means by which your email is accessed).
Server side spam processing is of course better, because you will benefit from it equally whether you're using your PC, phone and/or tablet to access your email. Your mail provider should handle that for you, but by marking mail as spam using the email client, you should improve the effectiveness of the spam filtering.
Email can be blocked using many methods, and a successful spam filtering solution will use a combination of them. Emails can be blocked/spammed when:
- it's received from servers on known blackedlisted IPs
- it's received from known blacklisted domains
- it's received from servers not authorised to send emails for the given domain by an SPF records
- it fails DKIM validation
- it's received from email servers in China/Russia/Brazil etc.
- It's from an unknown sender and contains multiple recipients
- It's from an unknown sender and it contains links
- It contains links to blacklisted domains or resolve to blacklisted IPs
- It is from an unknown sender and it has an attachment
- It contains an attachment identified as malicious
- You have 'spammed' similar emails
- The email is non-English
- Other email recipients have 'spammed' similar emails
- The email contains certain words (e.g. 'V1agra')
I've no doubt you have got access to some email hosting via your website host. It might be worth finding out about the email hosting packages they offer, in terms of what SPAM prevention methods are employed etc. ... You could contact them an ask. With the above list in mind, you will be able to judge for yourself whether or not they take SPAM prevention seriously. They also need to offer DKIM signing of the email you send to help ensure delivery.
