Once upon a time only big companies had the luxury to pay software developers thousands of pounds to integrate their software together. Low cost business apps paid on a small monthly subscription now means even a one man band can enjoy his bank talking to his accounting system which talks to his CRM which emails his news letters.
Cloud based accounting software such as Xero makes this collaboration possible being the backbone of any business, at last count there was over 100 other companies that integrated their apps with Xero. You can clip on and off different apps as your needs change and your not left with this huge monster that you only use 10% of, but pay 90% more than you have to.
Collaboration is the key, don't miss the "apportunity"!