Data crawling and data scraping are as challenging as exciting. While the opportunity for data crawling is larger, these are a few practical challenges in data crawling and scraping.

2. THE CHALLENGES IN CRAWLING THE WEB.

3. As an ever-evolving field, extracting data from the web is still a
gray area.
No clear ground rules regarding the legality of web scraping
exists!
The concern over privacy issues on collecting data off the Web is
growing.
People are wary about how data is or can be used.

4. Increasingly, Big Data is being frowned upon.
Its harvesting, even more so!
Yet, undeniably, data crawling is growing exponentially.
As it grows, the Web is gradually becoming more
complicated to crawl.

5. CHALLENGE I
NON-UNIFORM STRUCTURES
Data formats & structures are inconsistent in the Web space.
Norms on how to build an Internet presence are non-existent.
The result?
Lack of uniformity and the vast ever-changing
terrains of the Internet.
The problem?
Collecting data in a machine-readable format
becomes difficult.

6. Problems increase with increase in scale!
Especially, when:
a) structured data is needed, and,
b) large number of details are to be extracted from
multiple sources.

7. CHALLENGE II
OMNIPRESENCE OF AJAX ELEMENTS
AJAX and interactive web components make websites more
user-friendly. But not for crawlers!
The result?
Content is produced dynamically (and on-the-go) by the
browser and therefore not visible to crawlers.
The problem?
To keep the content up-to-date, the crawler needs to be
maintained manually on a regular basis.
Even Google’s crawlers find it difficult to extract information!

8. Crawlers need to be refined in their approach to be more
efficient and scalable. We have a solution that makes crawling
AJAX pages prompt. Click here.

9. CHALLENGE III
THE “REAL” REAL-TIME LATENCY
Acquiring data-sets in real-time is a huge problem! Real-time
data is critical in security and intelligence to predict, report,
and enable preemptive actions.
The result?
While near-real-time is achieved, real-time latency
remains the Holy Grail.
The problem?
The real problem comes in deciding
what is and isn't important in real time.

10. CHALLENGE IV
WHO OWNS UGC?
User-Generated Content (UGC) proprietorship is claimed by
giants like Craigslist and Yelp and is usually out-of-bounds for
commercial crawlers.
The result?
Only 2-3 % sites disallow bots. Others believe in data
democratization, but it is possible these may follow suit
and shut access to the data gold mine!
The problem?
Site policing for web scraping and rejecting bots.

11. CHALLENGE V
THE RISE OF ANTI-SCRAPING TOOLS
Tools like ScrapeDefender, ScrapeShield, ScrapeSentry are
capable of differentiating bots from humans.
The result?
Restriction on web crawlers via e-mail obfuscation, real-
time monitoring, and instant alerts etc.
The problem?
This is <1%, yet it may rise; all thanks to rogue crawlers,
responsible for multiple hits on target servers.
DDoS becomes unavoidable!

12. Web data is a vast uncharted territory full of bounty, and
having the proper tools helps.
So does knowing how to use them since there exists a very
thin line between being ‘crawlers’ and ‘hackers’.
And this is where the genuine concern for privacy arises.
At PromptCloud, these crawling challenges are met head-on.
Our two ground rules we recommend that every web-crawling
solution should follow.

13. COURTESY
In our experience, a little courtesy goes a long way.
Burdening small servers and causing DDoS on target sites is
easy.
Yet it is detrimental to the success of any company – especially
small businesses!
Rule #1 is to allow at least an interval of 2 seconds in
successive requests.
This helps avoid hitting servers too hard.

14. CRAWLABILITY
Many (and most) websites restrict the amount of data (either
sections of the site or complete sites) that can be crawled by
spiders via the robots.txt file.
Rule #2 is to establish feasibility of such site(s)!
It helps greatly to check the site’s policy on bots — whether it
allows bots in target sections from where data is desired.